Dealing with Windows 10 Memory Usage

For the last 6 months or possibly more, I've been having problems with Windows 10 eating up far more RAM/Memory than it should be, I'd tried RAMMap, different Task Managers, killing processes and services.
But none of those seemed to help.

In the end what did it for me was Disabling Cortana and Onedrive using Group Policy. (Note: To do this using Group Policy you'll need to be on Windows 10 Pro or Enterprise)

To do this you can find the options under the following:
Cortana: Computer Configuration/Administrative Templates/Windows Components/Search/"Allow Cortana" and change state to "Disabled"

OneDrive: Computer Configuration/Administrative Templates/Windows Components/OneDrive/"Prevent the usage of OneDrive for File Storage" and set that to "Enabled"

After you've done that just restart your PC and it'll apply the settings.

I suspect the reason this worked for me has something more to do with Cortana and SearchUI.exe more than it does to do with OneDrive, But since I wasn't using OneDrive anyway it didn't really matter if I disabled it too.